Platelets from humans and other species have been used to continue the study of amine uptake, amine metabolism, amine storage, and amine release. Since these processes have been shown to possess a complex interrelationship in intact platelets, similar processes in model systems, mitochondria, nerve microsacs, and microvessels have been examined to explore more completely the nature of the individual components. In addition, some of the new techniques developed utilizing normal platelets have been applied to the study of platelets from patients with disorders of amine storage. The results provide a fundamental basis for understanding the normal and pathological regulation of aminergic systems in platelets and brain tissue, and suggest strategies for pharmacological alteration of this regulation.